Catalyst system for the Ziegler-Natta polymerization of olefins

ABSTRACT

Described are catalyst systems having aluminium alkyl complexes of the formula (I) described herein applied to magnesium chloride, SiO 2  or SiO 2  in combination with MgCl 2  as support in the presence of titanium halides or vanadium halides and internal and, if desired, external donors act both as cocatalysts and as stereoselectivity promoters in heterogeneous polymerizations of α-olefins. Also described are polymerization methods using these catalyst systems.

[0001] The invention relates to novel catalyst systems characterized inthat aluminium alkyl complexes of the formula (I), such as described inDE 19753135 applied to magnesium chloride, SiO₂ or SiO₂ in combinationwith MgCl₂ as support in the presence of titanium halides or vanadiumhalides act both as cocatalysts and as stereo-selectivity promoters inheterogeneous polymerizations of α-olefins,

[0002] where

[0003] X¹ is NH, NH₂*, NH—A*, NH—SiA₃*, N—A, NSiA₃, N(A)₂*, N(SiA₃)₂*,O, OSiA₂, OA*, OSiA₃*, OAryl*, S, SSiA₂, SA*, SSiA₃*, PA, PSiA₃, P(A)₂*,P(SiA₃)₂* or a single bond,

[0004] X² is NH, N—A, NSiA₃, O, OSiA₂, S, SSiA₂, PA or X¹ coordinated toAl(R¹)₃, or a single bond,

[0005] R¹ is H; Hal when n=0; A, if desired covalently bound to Al;Si(A)₃ when X¹═O,

[0006] R² is A, if desired covalently bound to Al;

[0007] CH₂—CH═CH, CH₂—C≡C when Z¹═H;

[0008] R³ and R⁴ are each, independently of one another, a bond or R² orSi(A)₃ or Si(A)₂,

[0009] Z¹ is a bond or H bound to R²,

[0010] Z² is a bond or H bound to R² and R³,

[0011] where

[0012] A is branched or unbranched C₁-C₇-alkyl, -alkylidene or-alkenylidene,

[0013] Aryl is phenyl, naphthyl, indenyl, fluorenyl,

[0014] Hal is F, Cl,

[0015] and, independently of one another,

[0016] n is 0 or 1,

[0017] m is 0 or 1,

[0018] p is 0 or 1,

[0019] q is 1 or 2,

[0020] l is 0 or 1,

[0021] where coordinate bonds can exist between X¹, X² and Al, and R¹,R², R³, R⁴, X¹, X², Z¹ and Z² can, in each case independently of oneanother at different positions in the molecule, assume all meanings andX¹ can assume only the meanings denoted by “*” when 1=0 and R¹, R², R³orR⁴ are not present.

[0022] Ziegler-Natta-catalysed polymerization is a polymerization methodwhich has been improved over a number of generations since the initialwork by Ziegler and Natta in the 1950s. Seeking to increase both theactivity and the stereoselectivity has been the driving force for thecontinuous development of the catalyst system. The system established atthe present time is based on the use of a multicomponent catalyst. Inaddition to the support material, this comprises as actual catalyst atransition metal compound, e.g. a titanium compound, which is activatedonly by addition of an aluminium-containing cocatalyst. In addition,further constituents such as internal and external donors are necessary.The use of an internal donor prevents agglomeration of the catalyticallyactive species, while the external donor improves the stereospecificitywhen using prochiral olefins. Thus, in a polymerization using liquidpropene, the system MgCl₂/ester/TiCl₄/AlEt₃/PhSi(OEt)₃ makes it possibleto achieve a productivity of 600 [kg_(PP)/g_(Ti)] combined with anisotacticity of 98%. These catalyst systems save the costly removal ofcatalyst residues and the complicated extraction of atactic materialfrom the polyolefins produced. The understanding which has now beengained regarding the relationship between catalyst and polymermorphology makes it possible to control the polymer morphology duringthe polymerization process, which eliminates additional processing stepssuch as extrusion and granulation. These advances have for the firsttime made it possible to carry out solvent-free gas-phase polymerizationand bulk polymerization and have led to substantial simplifications inthe case of suspension polymerization. [P. Galli, J. C. Haylock,Makromol. Chem., Macromol. Symp. 1992, 63, 19-54; P. Corradini, V.Buscio, G. Guerra, in Comprehensive Polymer Science, Vol. 4, G. Allen(Ed.), Pergamon Press, 1999, p. 29; C. Jenny, P. Maddox, Solid State &Mat. Science 1988, 3, 94; K. Soga, T. Shiono, Progress in PolymerScience 1997, 22, 1503].

[0023] DE 19753135 describes a series of aluminium compounds which havean intramolecular donor side chain, e.g. an amino-, thio- oroxo-coordinated side chain, and can be prepared by methods known tothose skilled in the art for preparing organometallic compounds. Thesealuminium compounds act as cocatalytically activating components inZiegler-Natta catalysts for the polymerization of ethylene. However, thepolymerization of propylene or higher α-olefins cannot be carried outsuccessfully using the catalyst systems described in this patentapplication. Furthermore, the catalyst systems used there did notinclude a catalyst support, which makes them difficult or impossible touse in industrial plants and additionally does not allow the desiredpolymer morphology to be set.

[0024] Apart from the continual striving for more active and moreselective catalyst systems, the following aspects are in need ofimprovement:

[0025] a) The catalyst systems used in industry comprise highlypyrophoric, reactive, volatile aluminium alkyl compounds as cocatalysts,in particular triethyl-aluminium. These compounds are highly sensitiveto impurities in the reaction medium, for example to residual moisturein the monomers to be polymerized. In addition, the safe handling ofsuch highly pyrophoric and volatile compounds requires expensive safetycontainers for storage and transport under absolute exclusion of oxygenand moisture. Furthermore, the industrial plants for catalystpreparation and polymerization have to be able to cope with theseproblems. This is, in particular, a problem for industrially relativelyundeveloped countries and regions in which high temperatures and highatmospheric humidity prevail as a result of the climate.

[0026] b) To be able to achieve further increases in the yield ofpolymers in olefin polymerization, catalyst systems having higheractivities have to be tailored and developed. The activity increaseshould be able to be achieved by optimization of the cocatalyst, sinceit converts the catalyst into the actual catalytically active species.

[0027] c) To achieve high stereoselectivities in the Ziegler-Nattacatalysis of prochiral olefins, additional costly external donors suchas PhSi(OEt)₃ have to be used. The properties (tacticity and molecularweight distribution) of the polymers obtained using external donors havehitherto not been able to be optimized fully satisfactorily, so thatthere is a continuing need for polymers having improved properties.

[0028] d) Since the cocatalyst in Ziegler-Natta catalysts is usuallyused in a large excess relative to the catalyst and is thus the mostcostly component, there is great interest in reducing thecocatalyst/catalyst ratio while retaining the activities.

[0029] It is therefore an object of the present invention to providecatalyst systems which do not have the disadvantages listed under a),b), c) and d) and can be used both for the polymerization of ethyleneand of propylene and higher α-olefins. Another object of the presentinvention is to provide corresponding catalyst systems which are boundto suitable supports, simply and inexpensively. The catalyst systems ofthe present invention should be usable in industrial plants under simpleconditions with a relatively small cocatalyst/catalyst ratio and shouldat the same time have activities which are better than those ofpreviously known systems. Another object of the present invention is toprovide corresponding catalyst systems which are less sensitive toimpurities, in particular moisture.

[0030] Upon further study of the specification and appended claims,further objects and advantages of this invention will become apparent tothose skilled in the art.

[0031] The invention includes catalyst systems comprising

[0032] a) aluminium alkyl complexes of the formula (I)

[0033] where

[0034] X¹ is NH, NH₂*, NH—A*, NH—SiA₃*, N—A, NSiA₃, N(A)₂*, N(SiA₃)₂*,O, OSiA₂, OA*, OSiA₃*, OAryl*, S, SSiA₂, SA*, SSiA₃*, PA, PSiA₃, P(A)₂*,P(SiA₃)₂* or a single bond,

[0035] X² is NH, N—A, NSiA₃, O, OSiA₂, S, SSiA₂, PA or X¹ coordinated toAl(R¹)₃, or a single bond,

[0036] R¹ is H; Hal when n=0; A, if desired covalently bound to Al;Si(A)₃ when X¹═O,

[0037] R² is A, if desired covalently bound to Al;

[0038] CH₂—CH═CH, CH₂—C≡C when Z¹═H;

[0039] R³ and R⁴ are each, independently of one another, a bond or R² orSi(A)₃ or Si(A)₂,

[0040] Z¹ is a bond or H bound to R²,

[0041] Z² is a bond or H bound to R² and R³,

[0042] where

[0043] A is branched or unbranched C₁-C₇-alkyl, -alkylidene or-alkenylidene,

[0044] Aryl is phenyl, naphthyl, indenyl, fluorenyl,

[0045] Hal is F, Cl,

[0046] and, independently of one another,

[0047] n is 0 or 1,

[0048] m is 0 or 1,

[0049] p is 0 or 1,

[0050] q is 1 or 2,

[0051] l is 0 or 1,

[0052] where coordinate bonds can exist between X¹, X² and Al, and R¹,R², R³, R⁴, X¹, X², Z¹ and Z² can, in each case independently of oneanother at different positions in the molecule, assume all meanings andX¹ can assume only the meanings denoted by “*” when 1=0 and R¹, R², R³or R⁴ are not present,

[0053] b) magnesium chloride, SiO₂ or SiO₂ in combination with MgCl₂ assupport material,

[0054] c) a catalyst selected from the group consisting of titaniumhalides and vanadium halides and

[0055] d) internal donors such as mono esters or diesters, e.g. ethylbenzoate, dimethyl phthalate, or internal donors with which thoseskilled in the art are familiar and, if desired, also external donorsselected from the group consisting of compounds RSi(OR)₃, e.g.PhSi(OEt)₃, or external donors with which those skilled in the art arefamiliar.

[0056] In particular embodiments the invention is achieved bycorresponding catalyst systems comprising at least one aluminium alkylcomplex of the formula (I) selected from the group consisting of

[0057] [3-(dimethylamino)propyl]dimethylaluminium,

[0058] [3-(dimethylamino)propyl]methylaluminium chloride,

[0059] [3-(diethylamino)propyl]diethylaluminium,

[0060] [3-(diethylamino)propyl]dipropylaluminium,

[0061] [3-(diethylaminno)propyl]dibutylaluminium,

[0062] [4-(diethylamino)butyl]dibutylaluminium,

[0063] [3-(dimethylamino)propyl]aluminium dichloride,

[0064] [2-(dimethylamino)benzyl]diethylaluminium,

[0065] [3-(dimethylamino)benzyl]ethylaluminium chloride,

[0066] [2,6-bis(dimethylaminomethyl)phenyl]diethylaluminium,

[0067] [8-(dimethylamino)naphthyl]dimethylaluminium,

[0068] [8-(dirnethylamino)naphthyl]diethylaluminium,

[0069] 1-[3-(dimrethylamino)propyl]-1-aluminacyclohexane,

[0070] 1-[3-(dimethylamino)-2-methylpropyl]-1-aluminacyclo-hexane,

[0071] 1-[3-(dimethylamino) propyl]-1-aluminacycloheptane,

[0072] bis[3-(dimethylamino)propyl]methylaluminium,

[0073] 1,5-dimethyl-1-alumina-5-azacyclooctane,

[0074] 1-ethyl-5-methyl-1-alumina-5-azacyclooctane,

[0075] 1-alumina-5-azabicyclo[3.3.3]undecane,

[0076] [4-(methoxy)butyl]dimethylaluminium,

[0077] [3-(ethoxy)propyl]diethylaluminium,

[0078] [3-(ethoxy) propyl]dibutylaluminium,

[0079] [3-(propoxy) propyl]dibutylaluminium,

[0080] [4-(ethoxy)butyl]dibutylaluminium,

[0081] [5-(ethoxy)pentyl]dibutylaluminium,

[0082] [3-(ethylthiopropyl)diethylaluminium,

[0083] [3-(ethylthiopropyl)dibutylaluminium,

[0084] bis{[2-(dimethylamino)ethoxy]dimethylaluminium}

[0085] bis{[2-(dimethylamino)ethoxy]diethylaluminium}

[0086] bis{[2-(diethylamino)ethoxy]diethylaluminium}

[0087] bis{[3-(diethylamino)propoxy]diethylaluminium}

[0088] bis{[2-(dimethylamino)ethoxy]dibutylaluminium}

[0089] bis{[2-(methoxy)ethoxy]dimethylaluminium}

[0090] bis{[3-(methoxy)propoxy]dimethylaluminium}

[0091] bis{[2-(methoxy)ethoxy]diethylaluminium}

[0092] bis{[2-(methoxy)ethoxy]dibutylaluminium}

[0093] bis{[2-(butoxy)ethoxy]dimethylaluminium}

[0094] bis{[2-(butoxy)ethoxy]dibutylaluminium}

[0095] bis{[2-(ethoxy)ethoxy]diethylaluminium}

[0096] bis{[2-(phenoxy)ethoxy]dimethylaluminium}

[0097] bis{[2-(methoxy)phenoxy]dimethylaluminium}

[0098] [2-(diethylamino)ethoxy]diethylaluminium·AlEt₃ adduct,

[0099] [3-(diethylamino)propoxy]diethylaluminium·AlEt₃ adduct,

[0100] [2-(methoxy)ethoxy]dimethylaluminium·AlMe₃ adduct,

[0101] [2-(methoxy)ethoxy]diethylaluminium·AlEt₃ adduct,

[0102] [2-(ethoxy)ethoxy]diethylaluminium·AlEt₃ adduct,

[0103] [3-(ethoxy)propoxy]diethylaluminium·AlEt₃ adduct,

[0104] [2-(methylthio)ethoxy]dimethylaluminium·AlMe₃ adduct.

[0105] The present invention therefore also provides for the use of sucha catalyst system in heterogeneous polymerizations of α-olefins andprochiral olefins, in particular of ethylene and propylene.

[0106] In these reactions, the catalyst system of the invention can beused as a stereoselectivity promoter. The polymer properties can becontrolled by selectively choosing the catalyst.

[0107] The present invention further provides a process for preparingcatalyst systems according to the invention for the polymerization ofα-olefins or prochiral olefins. Depending on the application, thepreparation can be carried out by

[0108] (a) applying a titanium or vanadium halide to MgCl₂ or SiO₂ or toa combination of SiO₂ and MgCl₂ as support and adding an internal donorsuch as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate,or internal donors with which those skilled in the art are familiar and,if desired, also external donors selected from the group consisting ofcompounds RSi(OR)₃, e.g. PhSi(OEt)₃ or external donors with which thoseskilled in the art are familiar and an aluminium compound of the formula(I). or by

[0109] (b) applying an aluminium compound of the formula (I) to MgCl₂,SiO₂ or SiO₂in combination with MgCl₂ as support and adding a titaniumor vanadium halide and adding an internal donor such as monoesters ordiesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donorswith which those skilled in the art are familiar and, if desired, alsoexternal donors selected from the group consisting of compoundsRSi(OR)₃, e.g. PhSi(OEt)₃, or external donors with which those skilledin the art are familiar, or by

[0110] (c) applying an active species generated from an aluminiumcompound of the formula (I) and a titanium or vanadium halide to MgCl₂or SiO₂ or to a combination of SiO₂ and MgCl₂ as support and adding aninternal donor such as monoesters or diesters, e.g. ethyl benzoate,dimethyl phthalate, or internal donors with which those skilled in theart are familiar and, if desired, also external donors selected from thegroup consisting of compounds RSi(OR)₃, e.g. PhSi(OEt)₃, or externaldonors with which those skilled in the art are familiar.

[0111] It has surprisingly been found that application of the aluminiumcompounds of the formula (I) to magnesium chloride or SiO₂ or to acombination of SiO₂ and MgCl₂ as support in the presence of titanium orvanadium halides and internal donors such as monoesters or dieszers,e.g. ethyl benzoate, dimethyl phthalate, or internal donors with whichthose skilled in the art are familiar and, if desired, also externaldonors selected from the group consisting of compounds RSi(OR)₃, e.g.PhSi(OEt)₃, or external donors with which those skilled in the art arefamiliar gives a catalyst system which, firstly makes possible thepolymerization of α-olefins, in particular propylene, in high yieldsand, secondly, leads to a tremendous increase in activity in thepolymerization of ethylene even at 30° C. compared with the unsupportedcatalyst systems. Various methods of application to the support havebeen developed:

[0112] (a) application of a titanium or vanadium halide to MgCl₂ or SiO₂or to a combination of SiO₂ and MgCl₂ as support and addition of aninternal donor such as monoesters or diesters, e.g. ethyl benzoate,dimethyl phthalate, or internal donors with which those skilled in theart are familiar and, if desired, also external donors selected from thegroup consisting of compounds RSi(OR)₃, e.g. PhSi(OEt)₃ or externaldonors with which those skilled in the art are familiar and addition ofan aluminium compound of the formula (I)

[0113] (b) addition of an aluminium compound of the formula (I) to MgCl₂or SiO₂ or to a combination of SiO₂ and MgCl₂ as support and addition ofa titanium or vanadium halide and addition of an internal donor such asmonoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, orinternal donors with which those skilled in the art are familiar and, ifdesired, also external donors selected from the group consisting ofcompounds RSi(OR)₃, e.g. PhSi(OEt)₃, or external donors with which thoseskilled in the art are familiar,

[0114] (c) addition of an active species previously generated from thetwo components to MgCl₂ or SiO₂ or to a combination of SiO₂ and MgCl₂ assupport and adding an internal donor such as monoesters or diesters-,e.g. ethyl benzoate, dimethyl phthalate, or internal donors with whichthose skilled in the art are familiar and, if desired, also externaldonors selected from the group consisting of compounds RSi(OR)₃, e.g.PhSi(OEt)₃, or external donors with which those skilled in the art arefamiliar.

[0115] The experiments carried out indicated that the method (A) givesthe highest activities during olefin polymerization. The use of selecteddonor-stabilized organoaluminium compounds also gives higher activitiesthan those achieved in the prior art.

[0116] It has been found that the polymer properties can be controlledby choice of the cocatalyst.

[0117] The catalyst systems of the invention can advantageously be usedunder conditions which assist the process. The latter is parzicularlythe case when using a cocatalyst/catalyst ratio lower than that hithertocustomary. In particular, the polymerization properties can becontrolled according to the invention by altering this ratio.

[0118] A further advantageous property which has been found is that thenovel catalyst systems are quite stable to air, moisture and impuritiesin the reaction system and thus require technically less demandingcontainers for storage and transport or technically less complicatedplants for the preparation of the catalyst and for the polymerization ofolefins. The novel catalyst systems also have a high thermal stabilityand long life under reaction conditions.

[0119] Furthermore, it has surprisingly been found that the novelcatalyst systems consisting of MgCl₂ or SiO₂ or a combination of SiO₂and MgCl₂, a titanium or vanadium halide compound, an internal donor andan aluminium compound of the formula (I) are also stereoselective in thepolymerization of prochiral olefins without addition of external donors.

[0120] The aluminium compounds of the formula (I) can thereforesimultaneously perform a plurality of functions in the novel catalystsystems: they act firstly as cocatalysts and secondly asstereo-selectivity promoters. This makes it possible to reduce thenumber of catalyst components necessary by one component. The thirdfunction is to control the molecular structure of the polymers, e.g.molecular weights, molecular weight distributions, tacticities andbranching, and thus the polymer properties such as hardness, stiffness,toughness, weldability, transparency, gas permeability andprocessability.

[0121] A reduction in the number of catalyst components also, inaddition to the higher thermal stability and lower oxygen and moisturesensitivity found, makes the processes for catalyst preparation andolefin polymerization generally easier.

[0122] The low oxygen and moisture sensitivity of the aluminiumcompounds of the formula (I), which makes more convenient and safehandling possible, is achieved by means of the intramolecularlystabilizing donor group with coordinative saturation of the aluminiumcentre.

[0123] As described, the novel catalyst systems consist of support,catalyst, donor and cocatalyst:

[0124] Cocatalysts employed are the aluminium compounds of the formula(I).

[0125] Catalysts employed are compounds oL transition metals oftransition groups IV to VIII of the Periodic Table of the Elements, inparticular compounds of transition metals of transition groups IV and Vof the Periodic Table, in particular titanium and vanadium halidecompounds. Examples of suitable compounds are TiCl₄ and VCl₄.

[0126] As catalyst support, it is possible to use anhydrous MgCl₂ orSiO₂ or a combination of SiO₂ and MgCl₂.

[0127] Donors used are internal donors such as monoesters or diesters,e.g. ethyl benzoate, dimethyl phthalate, or internal donors with whichthose skilled in the art are familiar and, if desired, also externaldonors selected from the group consisting of compounds RSi(OR)₃, e.g.PhSi(OEt)₃, or external donors with which those skilled in the art arefamiliar.

[0128] The preparation of the novel supported catalyst systems iscarried out by a process which is disclosed with the aid of examplesgiven in the following text. These examples are specific embodiments; aperson skilled in the art will, on the basis of his technical knowledge,be able to replace means indicated therein by corresponding means havingan equivalent action.

[0129] To prepare the supported catalyst systems, it is possible to useaprotic, nonpolar solvents such as pentane, hexane, heptane, octane,benzene or toluene as solvents.

[0130] It has been found that preferred active systems are obtained whenthe cocatalyst/catalyst ratio is in the range from 1:1 to 80:1, morepreferably from 5:1 to 20:1.

[0131] It has been found that the cocatalyst/catalyst ratio can bereduced in the novel catalyst systems without decreases in activityresulting. In addition, the use of the novel cocatalysts in thepolymerization of ethylene and propylene leads to an increase inactivity in comparison with conventional catalyst systems. In this way,the catalyst systems of the invention can be prepared considerably morecheaply than corresponding, previously known systems. Thecocatalyst/catalyst ratio can be reduced to values of from 20:1 to 1:1without the yields and the desired product quality being influenced to asignificant extent. Up to a ratio of about 2:1, no decreases in activityhave to be accepted. Even above a ratio of 1:1, high activities farabove those of conventional systems are achieved.

[0132] The catalyst concentration is preferably in the range from 10⁻²to 10⁻⁶ mol/l, more preferably from 10⁻³ to 10⁻⁵ mol/l.

[0133] The catalyst or cocatalyst loading on MgCl₂ is preferably in therange from 0.5 to 5 mmol/g, more preferably from 1 to 3 mmol/g.

[0134] Owing to their lower sensitivity to moisture and air and theirlower senstitivity to impurities when used in a polymerization, thenovel catalyst systems can be handled more safely and give morereproducible results and also a greater, long-term stability incomparison with systems of the prior art.

[0135] The entire disclosure of all applications, patents andpublications, cited above, and of corresponding German application No.10010796.6, filed Mar. 8, 2000 is hereby incorporated by reference.

[0136] Without further elaboration, it is believed that one skilled inthe art can, using the preceding description, utilize the presentinvention to its fullest extent. The following preferred specificembodiments are, therefore, to be construed as merely illustrative, andnot limitative of the remainder of the disclosure in any way whatsoever.

[0137] In the foregoing and in the following examples, all temperaturesare set forth uncorrected in degrees Celsius; and, unless otherwiseindicated, all parts and percentages are by weight.

EXAMPLES

[0138] a) Preparation of the Novel Catalyst Systems

[0139] Application of aluminium alkyl complexes of the formula (I) toMgCl₂ as support

[0140] Basis

[0141] Organoaluminium compound: n_(Al cocat)[mol]=m_(Al cocat)/M_(Al cocat)

[0142] MgCl₂: m_(MgCl2)=n_(Al cocat)/theor. loading[mol(Al)/g]-m_(Al cocat)

[0143] Hydrocarbon: 50 ml for a total amount of 3-8 g(m_(MgCl2)+m_(Al cocat))

[0144] Procedure

[0145] All work is carried out under protective gas. The hydrocarbonused is dried and distilled prior to the reaction. The organoaluminiumcompound and the magnesium chloride are placed in a baked-out flask withSchlenk attachment. The appropriate amounts are calculated from thedesired theoretical loading, which should be in the range 1-2×10⁻³ mol(Al)/g. Depending on the solubility of the organoaluminium compound,pentane, hexane, heptane, octane, benzene or toluene is added. Thereaction mixture is then stirred at room temperature for 12 hours. Thesolvent is subsequently removed at 60-120 mbar.

[0146] The theoretical loading is calculated according to the followingequation:

(m _(Al cocat) /M _(Al cocat))/(m _(Al cocat) +m _(MgCl2))=theor.loading [mol(Al)/g]

[0147] Supported Loading component [mmol/g]

1.8

1.3

1.0

1.0

1.5

1.5

1.5

1.5

[0148] Application of (3-dimethylaminopropyl) dimethylaluminium to MgCl₂as support

[0149] Basis

[0150] Al cocat: 1.77 g (1.2×10⁻² mol) M_(Al cocat)=143.21 g/mol

[0151] MgCl₂: 6.50 g (6.8×10⁻² mol) M_(MgCl2)=95.21 g/mol Pentane: 50 ml

[0152] Procedure

[0153] All work was carried out under protective gas. Pentane was driedand distilled prior to the reaction. The organoaluminium compound andthe magnesium chloride were placed in a baked-out 100 ml flask withSchlenk attachment. After addition of 50 ml of pentane, the reactionmixture was stirred at room temperature for 12 hours. The solvent wassubsequently removed at 100-120 mbar over a period of 2 hours. This gavea light-grey powder.

[0154] The theoretical loading was calculated according to the followingequation:

(m _(AlN1) /M _(Al cocat))/(m _(Al cocat) +m _(MgCl2))=1.5×10⁻³ mol/g

[0155] Application of TiCl₄ to MgCl₂ as support

[0156] Reaction Conditions and Procedure

[0157] Suspend MgCl₂ in 50 ml of pentane, add TiCl₄, stir for 12 hoursat 25° C. under an inert gas atmosphere, remove pentane at 80 mbar.Loading: 1:4 mmol/g.

[0158] b) Use of the Novel Catalyst Systems in the Polymerization ofOlefins

[0159] The polymerizatIon is carried out in a known manner in solution,suspension or the gas phase, continuously or batchwise, at a temperatureof from 0° C. to +200° C., preferably from +20 to +140° C., and apressure of from 1 to 20 bar, preferably from 2 to 10 bar. Hexane,heptane, octane, propene or toluene is used as solvent.

[0160] Olefins which are polymerized have the formula R^(a)—CH═CH—R^(b),where R^(a) and R^(b) are identical or different and are each hydrogenor an alkyl radical having from 1 to 20 carbon atoms, preferablyethylene, H₂C═CH₂, and propylene, MeHC═CH₂.

[0161] The novel catalyst systems make it possible to preparehomopolymers, copolymers and block copolymers, preferably thehomopolymers polyethylene and polypropylene.

[0162] The activities of the catalyst systems in the polymerization ofethylene and propylene are comparable to or better than those of MgCl₂,TiCl₄ and AlEt₃, but using a distinctly lower cocatalyst/catalyst ratio.

[0163] All the novel catalyst systems gave high molecular weight andfinely particulate polymers.

[0164] The molecular weights of the polyethylene samples are in therange 2·10⁶-8·10⁶ g/mol. The melting points vary from 135° C. to 140° C.The crystallinities are in the range from 40 to 80%. The polymer samplesare unbranched and linear.

[0165] The polypropylene samples have molecular weights of 4·10⁵-1·10⁶g/mol and a molecular weight distribution of 7-15, which is distinctlylower than that obtained using AlEt₃. The melting points vary from 150°C. to 160° C. The crystallinities are in the range from 30 to 60%.

[0166] The catalyst systems are, without addition of donors,stereoselective in propylene polymerization. ¹³C-NMR analyses of thepolypropylene samples show linear structures with isotactic sequencelengths having significantly higher frequencies of mmmm pentads comparedto those obtained using AlEt₃.

[0167] Polymerization of Ethylene and Propylene

[0168] All polymerizations were carried out under an argon gasatmosphere using Schlenk techniques. Solid catalyst and cocatalystcomponents were weighed out on an analytical balance in a BRAUNLabmaster 130 glove box. For a standard experiment, the substances wereintroduced into a 25 ml glass flask in such amounts that about 0.5·10⁻³mol of supported aluminium atoms could be used for the polymerization.The titanium tetrachloride used as catalyst was employed in the form ofa 0.1 mol/l stock solution in toluene. For experiments using supportedtitanium tetrachloride, a 0.1 mol/l suspension of the supported catalystwas prepared. The unsupported cocatalyst was weighed into a 25 ml glassflask in such an amount that about 0.5·10⁻³ mol of aluminium atoms couldbe used for the polymerization.

[0169] The polymerizations were carried out in a 11 glass autoclave fromBüchi. Before each experiment, the reactor was cleaned using ethanol andtoluene, hexane or heptane, evacuated at 95° C. by means of an oil pumpvacuum for one hour and during this time flushed a number of times withargon. The autoclave was charged successively with 195 ml of toluene,hexane or heptane and the supported cocatalyst suspended in 4 ml oftoluene, hexane or heptane. The temperature was adjusted to 30, 45 or60° C. The monomer was injected under a pressure of 2 or 10 bar. Afterthe suspension present in the reactor had been saturated with themonomer, the polymerizations were started by injection of 1 ml of a 0.1mol/l solution of titanium tetrachloride in toluene. In the case ofexperiments using unsupported aluminium alkyls and supported titaniumtetrachloride, the catalyst suspension was added first and thepolymerizations were then started by injection of a toluene, hexane orheptane solution of the cocatalyst. The isobaric reaction conditionswere maintained by the monomer supply of the reactor consisting of aBROOKS pressure regulator PC8606 and a BROOKS mass flow controller5850TR. The monomer consumption was recorded by means of a BROOKScontrol and display instrument model 5876 and a connected personalcomputer fitted with an A/D converter board, using the RTX Viewsoftware.

[0170] The polymerizations were slopped by injection of 5 ml of ethanol.The polymerization suspension was admixed with dilute hydrochloric acidand stirred overnight. The organic phase was neutralized using asaturated sodium hydrogen carbonate solution and washed with water. Thetoluene was removed in an oil pump vacuum until the mass of the polymerwas constant.

[0171] Polymer Analysis

[0172] The thermograms were recorded on a Mettler-Toledo differentialcalorimeter 821e at a heating rate of 20° C./min. The values obtained inthe second heating have been reported as the melting points.

[0173] The viscosity means of the molar masses M_(η) were determined bymeans of an Ubbelohde viscometer. The samples were prepared bydissolving about 50 mg of the polymer in 50 ml of decahydronaphthalene.The times for the polymer solutions to run out were measured by means ofa LAUDA Viskoboy. The Mark-Houwink constants were taken from T. G.Scholte, N. L. J. Meijerink, H. M. Schoeffeleers, A.M.G. Brands, J.Appl. Polym. Sci. 29 (1984) 3763.

[0174] The ¹³C-NMR spectra were recorded using a BRUKER-MSL 300instrument. For one measurement, usually 1000 scans were recorded at ameasurement frequency of 75.47 MHz and a temperature of 100° C. Thepulse angle was 60° and the relaxation delay was 6 s. The NMR sampleswere prepared by making up a solution of 10% by mass of polymer in amixture of perchlorobutadiene and 1,1,2,2-tetrachlorodideuteroethane.

[0175] Polymerization of Ethylene Using Aluminium Alkyl Compounds andTiCl₄ supported on MgCl₂

[0176] Polymerization conditions: T_(p)=30° C., p_(monomer)=2 bar,c_(Ti)=10⁻⁵ mol/l, Al/Ti=5 Activity [kg_(PE)/ T_(m) Crystallinity ηM_(η) · 10⁶ Cocatalyst (mol_(Ti)c_(ethene)h)] [° C.] [%] [ml/g] [g/mol]

90 136.8 39.7 n.d. n.d.

100 135.5 59.3 2050 3.10

480 131.2 54.0 1795 5.11

27 n.d. n.d. n.d. n.d.

700 132.5 53.3 n.d. n.d.

8 132.9 38.0 n.d. n.d.

320 132.3 53.5 n.d. n.d. AlEt₃ for 670 138.9 51.0 2254 3.53 comparison

[0177] Polymerization of Propylene Using Aluminium Alkyl Compounds andTiCl₄ Supported on MgCl₂

[0178] Polymerization conditions: T_(p)=30 °C., p_(monomer)=2 bar,c_(T1)=10⁻⁵ mol/l, Al/Ti=5 Activity [kg_(PE)/ T_(m) Crystallinity ηM_(η) · 10⁶ Cocatalyst (mol_(Ti)c_(propene)h)] [° C.] [%] [ml/g] [g/mol]

2 151.6 10.4 n.d. n.d.

8 152.8 23.8 333 0.704

3 145.8 15.2 393 0.886

12 n.d. n.d. n.d. n.d.

8 n.d. n.d. n.d. n.d. AlEt₃ 62 152.2 11.5 217 0.388

[0179] The microstructure of the polypropenes obtained usingMgCl₂/aluminium alkyl compounds and TiCl₄: Pentads Rel. Int. rmrr +n_(iso) [%] Mmmm Mmmr Rmmr mmrr mrmm mrmr rrr rrrm Mrrm

10 Rel. Int. [%] 57.9 9.1 1.4 0.0 9.7 6.0 2.7 8.0 5.3

5 Rel. Int. [%] 38.3 8.9 2.6 0.0 13.6 9.1 2.4 13.3 11.8 AlEt₃ for 7 Rel.Int. 46.5 10.9 2.9 0.0 12.8 8.7 2.9 8.7 6.5 comparison [%]

[0180] Polymerization of Ethylene Using MgCl₂/TiCl₄ and Aluminium AlkylCompounds

[0181] Polymerization conditions: T_(p)+30° C., p_(monomer)=2 bar,c_(T1)=10⁻⁵ mol/l, Al/Ti=5 Activity [kg_(PE)/ T_(m) Crystallinity ηM_(η) · 10⁶ Cocatalyst (mol_(Ti)c_(ethene)h)] [° C.] [%] [ml/g] [g/mol]

309 137.7 50.4 2020 3.03

480 136.4 46.9 2120 3.24

315 135.1 42.3 2210 3.43

105 137.4 42.6 n.d. n.d.

700 n.d n.d n.d. n.d.

15 n.d n.d. n.d. n.d.

23 n.d. n.d. n.d. n.d.

30 n.d. n.d. n.d. n.d.

1100 n.d. n.d. n.d. n.d. AlEt₃ for 600 139.1 53.0 1801 2.59 comparison

[0182] Polymerization of Propylene Using MgCl₂/TiCl₄ and Aluminium AlkylCompounds

[0183] Polymerization conditions: T_(p)=30 °C., p_(monomer)=2 bar,c_(T1)=10−5 mol/l, Al/Ti 5 Activity [kg_(PE)/ T_(m) η M_(η) · 10⁶Cocatalyst (mol_(Ti)c_(propene)h)] [° C.] [ml/g] [g/mol]

17 150.9   11.1 n.d.

145 154.4 309 0.634

95 148.5 346 0.740

2 n.d. n.d. n.d.

2 n.d. n.d. n.d. AlEt₃ for 155 151.0 186 0.312 comparison

[0184] The molecular weights and molecular weight distributions of thepolypropenes obtained using MgCl₂/TiCl₄ and aluminium, alkyl compounds:M_(n) M_(w) Cocatalyst [g/mol] [g/mol] M_(w)/M_(n)

55000 728000 13.4

60400 962000 15.9 AlEt₃ for 15500 441000 29.4 comparison

[0185] The micros,ructure of the polypropenes obtained using MgCl₂/TiCl₄and aluminium alkyl compounds: Pentads Rel. Int. rmrr + n_(iso) [%] MmmmMmmr rmmr mmrr mrmm mrmr rrr rrrm mrrm

8 Rel. Int. [%] 54.3 11.7 4.7 11.3 6.4 2.9 2.5 3.8 2.4

5 Rel. Int. [%] 36.9 10.2 2.5 13.8 8.8 1.8 14.3 7.0 4.8 AlEt₃ for 7 Rel.51.0 8.1 2.0 10.3 6.9 1.7 11.5 5.0 3.4 comparison Int. [%]

[0186] From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. A catalyst system comprising a) at least one aluminium alkyl complexof the formula (I)

where X¹ is NH, NH₂*, NH—A*, NH—SiA₃*, N—A, NSiA₃, N(A)₂*, N(SiA₃)₂*, O,OSiA₂, OA*, OSiA₃*, OAryl*, S, SSiA₂, SA*, SSiA₃*, PA, PSiA₃, P(A)₂*,P(SiA₃)₂* or a single bond, X² is NH, N—A, NSiA₃, O, OSiA₂, S, SSiA₂, PAor X¹ coordinated to Al(R¹)₃, or a single bond, R¹ is H; Hal when n=0;A, optionally covalently bound to Al; Si(A)₃ when X¹═O, R² is A, ifdesired covalently bound to Al; CH₂—CH═CH, CH₂—C≡C when Z¹═H;

R³ and R⁴ are each, independently of one another, a bond or R² or Si(A)₃or Si(A)₂, Z¹ is a bond or H bound to R², Z² is a bond or H bound to R²and R³, where A is branched or unbranched C₁-C₇-alkyl, -alkylidene or-alkenylidene, Aryl is phenyl, naphthyl, indenyl, fluorenyl, Hal is F,Cl, and, independently of one another, n is 0 or 1, m is 0 or 1, p is 0or 1, q is 1 or 2, l is 0 or 1, where coordinate bonds can exist betweenX¹, X² and Al, and R¹, R², R³, R⁴, X¹, X², Z¹ and Z² can, in each caseindependently of one another at different positions in the molecule,assume all meanings and X¹ can assume only the meanings denoted by “*”when 1=0 and R¹, R², R³ or R⁴ are not present, b) magnesium chloride,SiO₂ or SiO₂ in combination with MgCl₂ as support material, c) at leastone catalyst selected from the group consisting of titanium halides andvanadium halides and d) at least one internal and, optionally, also oneor more external donors selected from the group consisting of monoestersor diesters or the group consisting of compounds RSi(OR)₃ or R₂Si(OR)₂,where R are each, independently of one another, a branched or unbranchedC₁-C₁₀-alkyl group.
 2. A method comprising heterogeneous polymerizationof at least one α-olefin in the presence of a catalyst system ofclaim
 1. 3. The method of claim 2 wherein the at least one α-olefinincludes ethylene and propylene.
 4. A method comprising polymerizing atleast one prochiral olefin in the presence of a-catalyst system ofclaim
 1. 5. A method comprising polymerizing at least one olefin in thepresence of a catalyst system according to claim 1 as astereoselectivity promoter.
 6. A process for preparing a catalyst systemfor the polymerization of α-olefins or prochiral olefins, comprising (a)applying a titanium or vanadium halide to MgCl₂, SiO₂ or SiO₂ incombination with MgCl₂ as support and adding an aluminium compound ofthe formula (I) as described in claim 1, or by (b) applying an aluminiumcompound of the formula (I) as described in claim 1 to MgCl₂, SiO₂ orSiO₂ in combination with MgCl₂ as support and adding a titanium orvanadium halide or by (c) applying an active species generated from analuminium compound of the formula (I) and a titanium or vanadium halideto MgCl₂, SiO₂ or SiO₂ in combination with MgCl₂.
 7. A catalyst systemaccording to claim 1, comprising at least one aluminium alkyl complex ofthe formula (I) selected from the group consisting of:[3-(dimethylamino)propyl]dimethylaluminium,[3-(dimethylamino)propyl]methylaluminium chloride,[3-(diethylamino)propyl]diethylaluminium,[3-(diethylamino)propyl]dipropylaluminium,[3-(diethylaminno)propyl]dibutylaluminium,[4-(diethylamino)butyl]dibutylaluminium,[3-(dimethylamino)propyl]aluminium dichloride,[2-(dimethylamino)benzyl]diethylaluminium,[3-(dimethylamino)benzyl]ethylaluminium chloride,[2,6-bis(dimethylaminomethyl)phenyl]diethylaluminium,[8-(dimethylamino)naphthyl]dimethylaluminium,[8-(dirnethylamino)naphthyl]diethylaluminium,1-[3-(dimrethylamino)propyl]-1-aluminacyclohexane,1-[3-(dimethylamino)-2-methylpropyl]-1-aluminacyclo-hexane,1-[3-(dimethylamino) propyl]-1-aluminacycloheptane,bis[3-(dimethylamino)propyl]methylaluminium,1,5-dimethyl-1-alumina-5-azacyclooctane,1-ethyl-5-methyl-1-alumina-5-azacyclooctane,1-alumina-5-azabicyclo[3.3.3]undecane,[4-(methoxy)butyl]dimethylaluminium, [3-(ethoxy)propyl]diethylaluminium,[3-(ethoxy) propyl]dibutylaluminium, [3-(propoxy)propyl]dibutylaluminium, [4-(ethoxy)butyl]dibutylaluminium,[5-(ethoxy)pentyl]dibutylaluminium,[3-(ethylthiopropyl)diethylaluminium,[3-(ethylthiopropyl)dibutylaluminium,bis{[2-(dimethylamino)ethoxy]dimethylaluminium}bis{[2-(dimethylamino)ethoxy]diethylaluminium}bis{[2-(diethylamino)ethoxy]diethylaluminium}bis{[3-(diethylamino)propoxy]diethylaluminium}bis{[2-(dimethylamino)ethoxy]dibutylaluminium}bis{[2-(methoxy)ethoxy]dimethylaluminium}bis{[3-(methoxy)propoxy]dimethylaluminium}bis{[2-(methoxy)ethoxy]diethylaluminium}bis{[2-(methoxy)ethoxy]dibutylaluminium}bis{[2-(butoxy)ethoxy]dimethylaluminium}bis{[2-(butoxy)ethoxy]dibutylaluminium}bis{[2-(ethoxy)ethoxy]diethylaluminium}bis{[2-(phenoxy)ethoxy]dimethylaluminium}bis{[2-(methoxy)phenoxy]dimethylaluminium}[2-(diethylamino)ethoxy]diethylaluminium·AlEt₃ adduct,[3-(diethylamino)propoxy]diethylaluminium·AlEt₃ adduct,[2-(methoxy)ethoxy]dimethylaluminium·AlMe₃ adduct,[2-(methoxy)ethoxy]diethylaluminium·AlEt₃ adduct,[2-(ethoxy)ethoxy]diethylaluminium·AlEt₃ adduct,[3-(ethoxy)propoxy]diethylaluminium·AlEt₃ adduct,[2-(methylthio)ethoxy]dimethylaluminium·AlMe₃ adduct.
 8. A catalystsystem according to claim 1, wherein the cocatalyst/catalyst ratio is inthe range from 80:1 to 1:1.
 9. A catalyst system according to claim 1,wherein the cocatalyst/catalyst ratio is in the range from 20:1 to 5:1.